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AC problems

opster81 on Mon May 30, 2011 6:57 AM User is offline

Year: 2006
Make: mazda
Model: mazda3
Engine Size: 2.3l
Ambient Temp: 95
Pressure Low: 60
Pressure High: 100
Country of Origin: United States


Quick question, anybody replaced a mazda3 ac system before? what should the cost be? Can you usually flush a evaporator, or is that going to have to be replaced if debris is found in it?

My compressor seized up. So I replaced it with a new one along with the drier and expansion valve. I didn't flush anything since the seized compressor oil was completely clean and all oil at junctions looked fine.

I put about 7oz of r134 in (manual says 17oz), started compressor, and low side went to about 0psi, and climbed to 60 psi within about 10seconds, high side was at 100 psi. After about 10 seconds compressor starts to squeel. I have no idea why, I would think a obstruction would cause high high-side pressure and low low-side pressure. Anyways I screwed up something, so I'm going to take it in and have them do it.

Any ideas though of what could be wrong? This is keeping me up all night an I know I won't be able to stop thinking about it until I figure it out.

Details:
-ambient temp 95F
-static pressure 80psi
-low side 60psi
-high side 100psi
-about 5-6oz of oil in system (manual says 5.25oz)
-7oz of r134a (holds 17oz)
-stop filling system when I notice compressor was squeeling.

Thanks

Dougflas on Mon May 30, 2011 10:35 AM User is offline

probably not enough oil, bad rebuilt compressor, or system had crap in it.
WHY DID THE OEM COMPRESSOR FAIL????

HVACNY on Mon May 30, 2011 11:01 AM User is offline

Did you put the correct viscosity and amount of Pag oil in the new compressor.Most dont come with oil.A whiny compressor that was just installed is oil starved.

opster81 on Mon May 30, 2011 12:08 PM User is offline

I think there should be enough oil in it. I put 3.5 oz in the new compressor and only drained 2 oz out of the old one. The manual says the evaporator and condenser will hold 1.5oz if there not taken out. So that puts me at 5.0oz. at least. And maybe a little more if a full 2oz didn't leave the system when it was evacuated (manual says 2oz will leave system when its evacuated). System capacity is suppose to be 5.25 total.

I guess this is one problem I have...... How do you have any idea how much oil is in a system unless you replace everything, or at least flush it? I probably shouldn't have tried this myself in retrospect. Getting a good flush as a DIY job isn't probably a possibility, that's why I didn't try, figured if everything appeared clean I would just mess it up trying to push solvent through the lines with a compressor.

I have no idea why the OEM compressor failed. Another mistake of mine I'm sure, should have spent more time trying to figure that out. It wasn't a lack of oil in the system or r134, both were right where they were suppose to be. There doesn't seem to be any debris anywhere. I was assuming it was just a badly designed system. I've heard a lot of people complain about the Mazda3 compressors. It's made by Panasonic, and if you go to their site:

http://pwcg.panasonic.cn/en/car/?nid=991&Ln=ln1-1

you'll see they have a oil separator feature. Makes me think it is a bad idea and leads to poor lubrication. I took the oil reservoir cover off the seized compressor and saw no signs of debris in the reservoir, and the high pressure port enters the compressor through the oil cover, so if debris was in the system from the compressor you would figure you would see it there first.

So my guess is there was enough oil in the systems but it wasn't reaching the bearings and pressure chamber of the compressor properly. But this my first AC job/failure so I'm sure I'm wrong. There probably is debris somewhere, but it just doesn't make sense, should be seeing high high-side and low low-side.

Any more thoughts? New compressor still rotates fine. Noise is belt slipping not a mechanical noise. When AC first starts compressor will engage and turn fine, after about 5 seconds though the noise comes and I can see the compressor is barely turning and belt is slipping. That occurs at about low/high side pressure readings of 60/100.

iceman2555 on Mon May 30, 2011 6:19 PM User is offlineView users profile

The condenser is severely restricted...hence the lock up at operation and rotation by hand and lock up under pressure.
The system has not way been serviced correctly....there is no compressor produced that will survive under the conditions of this repair. The system should be totally flushed...yes..so that one knows how much lubricant is in the system. No debris in the certain parts of the system does not mean it is not in the system....normally it is located in the inlet side of the condenser.....a common characteristic of a compressor failure. The condenser of this vehicle utilizes a Parallel Flow High Efficiency, Sub Cooling, Modulated Condenser. This condenser is actually two separate condensers in one assembly. The flow orifices in the condenser may be a small or large as .010-.013 in. in diameter. The condenser has become the primary filter for many of the late model AC systems.
This repair should have included a new condenser, new TXV, a complete evaporator and hose assembly flush. The correct lubricant, type and quantity, added to the system. The system should be professionally recharged. There is no way to properly recharge this system utilizing cans and pressures. System requirements are 1.05 lbs of refrigerant (16.8 oz). Lube is 5 oz of PAG 46. An undercharge of this system by as little as 1 oz can seriously effect lubricant flow....resulting in a repeat compressor failure.
Good luck with your repair.


-------------------------
The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

opster81 on Mon May 30, 2011 9:06 PM User is offline

Thanks Iceman, for what it's worth I think your spot on. Just got done taking original seized compressor apart and a vane had snapped in half and probably instantly seized the compressor. There isn't much debris, but 10 thou condenser passages wouldn't need much. Here's a pic of the failed OEM compressor:

So I'm taking it to a shop tomorrow, I have burnt enough money for awhile. Is it safe to assume any AC shop doing the work will flush the evaporator and replace the conditioner, or is that something I'm going to have to specifically ask for?

I'm in Mesa, AZ by the way, any suggestions of where to go?

opster81 on Mon May 30, 2011 9:09 PM User is offline

Sorry I meant "Is it safe to assume any AC shop will replace the condenser and flush the evaporator?" or do I have to specifically ask for that.

Also do you think the original compressor failed due to a clogged condenser? The OEM had a healthy film of oil in the compression chamber, so lack of lubrication didn't look like an issue.

Thanks, great forum!

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